Shock absorber



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" c. Nd MITCHELL SHOCKAABSORBER Filed May 26, 1924 4 Sheets-Sheet 2 INVETOR. Courtney N. Mitchell Jan. 22, 1929.

C. N. MITCHELL,

SHOCK ABSORBER Filed May 26, .1.924 x L1"Sheets-Sheet" [Nl/E NTOR. Courtney N. Mitchell BY l Mb# A TT() 4 Sheets-Sheet 4 INVENTOR. CQuTney N. Mitchell BY 7;

Mfg

3mm, E, 1929.

c. N. MWCHELL SHOCK ABSORBER/ Filed May 26, 1924 Patented Jan. 22, 1929.

COURTNEY`N. MITCHELL, F CLEVELAND, OHI,

SHOCK ABSORBER.

Application led Hay 26,

This invention relates,` as indicated, to shock absorbers, referring more particularly to that type of shock absorber which is adapted to be interposed between an automobile frame or chassls and the axle to brake the rebound of the frame, as when it moves upwardly away from the axle. In general practice the shock absorber and its enclosure'is mounted on the frame of an automobile above lo the axle, and the braking mechanism thereof connected by a strap, or other suitable means, to the axle. The object of this invention is to provide in a shock absorber of the above described character an improved mechanism for braking or retarding such rebound, which mechanism is contained by, and operable upon, the yinterior of an enclosing casing or brake drum. The same permits the use of approximatel the entire outer -dimension of the shock a sorber casing for the application of the braking means, thus providing a 'selfcontained' unit of minimum dimensions.

A further object is to provide a shock absorber which is adapted to operate to brake the shock of the movement ofthe axle toward the vehicle frame, as well as to retard movement of the axle in the opposite direction, it being of course desirable to have the braking action of the shock absorber of much lesser degree when'the'axle is moving upward than when the frame rebounds therefrom.

Anotherobject of my'invention is to provide an inexpensive, simplified type of connecting means which is adapted to connect the operating mechanism of the shock absorber to the axle of a vehicle. To the accomplishment of the 4foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description'set forth in detail certain mechanism embodying the invention, such dis-` closed means constitutin however, but. one of various mechanical ormsin which the principle of theinvention'm'ay be used.

In said annexed drawings Fig. 1 is a sectional view of' my novel shock absorber; v Y

Fig.2 is a transverse axial sectional view of the absorber taken on line 2 2, in-Fig. 1; Figs. 3 and 4 are views similar to Figs. 1 and 2 of a modified type of the invention, said figures being taken on line 3-"3, in Fig. 4, and 4 4 in Fig. 3, respectively;

1924. Serial No. 715,852.

Fig. 5 is a fragmentary View -of a vehicle frame and axle illustrating the manner of yattachment of the present shock absorber shown in Figs. l and 2;

Fig. 6 is a side elevation of my improved connecting means; i

Fig. -7 is an elevation at right angles to F is 6;

Fig. 8 is a View similar to Fig. 2 showing a modified construction.

Fig. 9 is a sectional view taken on the line 9-9 in Fig. 8; and Fig. 10 is a diagrammatic view illustrating the convergence between the brake drum and shoe pivotal bearing of this invention. 70

Referring now to the embodiment of my invention illustrated in Figs. 1, 2 and 6, 10 designates a anged hub member which is adapted to be attached to the side of a vehicle frame or chassis 1-1 by any suitable means, such as a bolt 12. The bolt 12 herein is screw threaded in the hub 10 and has its forward end projecting through a hollow boss portion 14, integrally formed on the front side of member 10. Enclosing the outer end of boss 14 is a flanged brake drum 15, which is rotatably held by' suitable means, to be presently described, so as to be circumferentially movable with `respect'to the axis of the hub boss 14`andthe bolt 12. The drum consists of an annular flange or bra a band 16. against the inner surface of which the shock absorbing or y braking mechanism of this invention frictionally engages, and' of a vertical front side 17. y

As is usual in the present type of shock absorbers, the brakin action of the various mechanisms result rom the rotation of the drum band 16 in one direction. During the reverse movement of such band the brake means are, automatically rendered inoperative. Many designs of connections may be v utilized for connecting the drum 15 to the axle 18 of an automobile, so that when in use, as the axle is moved'toward and away from'the' 100 vehicle chassis, the drumis caused to oscillate. As seen in Figs. 1, 2 and 6, the drum 15 is provided with a radial arm 20, to the outer end of which suitable connection is made to the axle 18. Such arm may be formed integral with the drum, or, as shown, with an annular ring portion 22 adapted' to be secured around the outer .surface of the drum band 16.

As has' been heretofore stated the braking ried internally of the drum and is adapted to engage the inner periphery of band 16. Such mechanism consists essentially of a plurality of segmental brake shoes, each having a strip of frictional brake material 19 on their outer surfaces. Means for mounting the shoes consists of equidistantly spaced pairs of radially projecting lugs 23 and 24. As best seen in Fig. 2, each pair of these lugs is provided with aligned apertures 25, one or both of which may be screw threaded as at 26 for the reception of pivotal pins 27. The brake shoes indicated by numerals 28 are formed at one end with inwardly extending bosses 29 adapted to be received between the pairs of lugs 23 and 24, and such bosses have transverse apertures 30, through which is passed the pins 27. Suitable bearings 31 may be used between the pins 26 and the apertures 30. Springs 32, seated in sockets 33, provided on the inner side of the shoes and having their outer ends bearing against t-he hollow boss 14, are employed to maintain the brake shoes pressed into frictional engagement at all times with the drum band 16.

One of the main objects of the present in` vention is to provide a simply constructed shock absorber having an external rotatable brake drum and a plurality of brake shoes c0- operating therewith to retard the movement of such drum in one direction. The' herein described novel mechanism accom lishes this function in a very much more e ectiveand improved manner over the mechanisms of previously designed shock absorbers. Taking for example, the arrangement of one of the shoes (in Fig. 1), together with its point of pivotal mounting and the relative position of the brake band, it will `be seen that the brake band is concentrically movable about its axis and about the outer periphery of the friction surface of the brake shoes when the latter are in normal or inoperative position. It will also be seen that the pivotal points ofthe shoes and the outer peripheries thereof are of eccentric relation. To aid in the understanding of the braking operation of the present shoes certain characters are placed on Fig. 1. T designates the point of tangent of the path of travel of the brake band 16 relative to the pivotal point P of shoe A, and B any point on the outer periphery of said shoe to the right of the point T. Consequently, if the point B be moved to the left the friction surface at that point of the shoe, dueto the eccentric relation of the point P, will become wedged against the inner surface ofthe brakeband 16 and cause a braking action of the movement of Athe brake drum. Likewise, the entire outer surface of the brake shoe, on account of its construction, will be forced into tight engagement with the brake drum during its rotation to the left.

In the reverse movement (to the right of the drawings), it will be obvious that such wedging or braking action of the shoes will be relieved, and'only the pressure of springs 32 will be effective at that time. Inasmuch as it 'is found desirable to retard to a lesser de gree the sudden movement of an axle toward the chassis of a vehicle the springs 32 may be designed to force the brake shoes linto tight enough engagement with the drum band 16 to sutliciently brake such movement.

yFurther details in the construction of the embodiment of the invention shown in Figs. 1 and 2 consist of a dust plate 40 screwed to the rear face of bosses 23 and a flange 41 circumferentially provided on member 14 yin alignment with such bosses. For simplicity of construction the pins 27 extend through such plate and a lock nut 43 and washer are secured on the outer end thereof. Plate 40 has an inturned annular fiange member 42 which is adapted to ovcrlie the outer surface of the brake drum band 16, and thus prevent any dirt from entering the interior of the drum at that point. Mounted on the out-er end 45 of bolt 12 is a disk washer 46 adapted to prevent the drum 15 from moving latterally, there being interposed a rin of packing material 47 between the disk an the side 17 of the drum. Contained in the hollow portion of the boss 14, and surrounding the bolt 12, is a spacing tube 48, against the end of which ythe disk 46 is held by nut 49. As seen in Fig. 2, t-he front edges 50 of the frictional brake material 19 are extendedslightly beyond the edge of the brake shoes, and these edgesv 50 curve inwardly for the purpose of engaging the inner side of plate 17.

It will be seen from the foregoing that the brake drum is held in assembled position only by the brake shoes, and by the rounded ends 50 ofthe friction unit, and the disk washer 46, which construction is very simple and permits the self-aligning of the brake drum without difficulty.

I have shown'in Figs. 8 and 9 a modifica.- tion of the embodiment described above by which adjustment may be given to the pressure of springs 32 to compensate for the wear of the friction material on the brake shoes. In such modification, the forward end 100 ot the hub member 14 is provided on its exterior with a cylindrical bearing surface 101 upon which is rotatablyv mounted an annular sleeve 102 of an adjusting member 103. The outer surface of sleeve 102 is provided with a series of equidistantly spaced c'am lugs 104 against which the inner ends of springs 32 bear, it being obvious that the tension or pressure of the springs may be increased by merely rotating the member 103 to present a higher portion of the cams in engagement with such springs. The outer end of member 103 is reduced in size and has a hole 105 therein through which is passed the end 45 of the bolt 12.

To facilitate the adjustment of member 1063 from the exterior ofthe shock absorber, the outer reduced 'end of said member is nonrotatably secured to the disk washer 46 as by a suitable spline 106. It will be seenl therefore that by turning the washer 46, the

adjustment of cams 104 is changed. To lockl the parts in adjustment, a nut 107 is secured on bolt 45 outside the washer, thus serving to firmly hold the sleeve 102 on the hub from rotation. It will further be seen that by the use of the construction described above, the spacer tube 48 may be eliminated, in which case the adjustable member 103 serves to limit the lateral movement of the washto be mounted on the side of a vehicle chassis by means of bolt 51 anchored therein. Member 50 is formed with an outwardly projecting hollowboss 52 which is provided at its outer end with an interior cylindrical bearing surface 53, in which is rotatably seated an inwardly projecting annular hub or journal 54 formed upon a drum 55.

The drum 55 is also provided with an inturned flange portion 56 at its outer rim, which flange serves as a brake band similar to the band 16, as will presently appear. Means for retainingr the drum in place on the bearing 53 is shown in the form of a disk 57 mounted on the forward projecting end 58 of bolt 51. There may be also utilized a spacer tube 59 interiorly fitted within the hollow boss 52 to prevent disk 57 from bearing too tightly against the drum.

The braking mechanism is here also carried internally of the drum, such mechanism comprising two or more brake shoes 60 pivotally mounted at one end upon pins 61, which are secured in pairs of lugs 62 and 63, projecting radially from boss 52. Each brake shoe is arcuate in form, with its outer surface concentric to the band portion 56 lof the drum 55, and has pads or layers of friction brake material attached to said outer surface. 1t is found that in forming the shoe as shown in Fig. 4 with its ends terminating substantially diametrically of the brake drum, the greatest amount of friction or wedging action occurs at the endsof the shoe as it is moved into engagement with the drum. Therefore, in 4some, cases, it is advantageous to provide the friction material only at the ends of the shoe, otherwise the central portion thereof would tend to hold the ends away from the desired wedging action. Springs 65, received in the sockets 66 provided in the inner sides i ofthe shoes 60 and engaging the boss 52, tend to keepthe brake shoes pressed outwardly' into engagement with the inner periphery of the drum. These brake shoes co-operate with the brake drum upon rotation of the drum to the left to retard such rotary movement, as has been hereinbefore described with relation to the lshock absorber of Figs. 1 and 2, but in thisembodiment the shoes are not adapted to exert any braking action upon the drum in its reverse movement.

Means for connecting the brake drum 55 to thev axle of a vehicle is shown in the form of the usual strap 70, which is wrapped around the exterior of thebrake band 56 and has its end attached to said .drum as at 71.l The other end of the strap is attached in any well known manner, not shown, to the axle of the vehicle, it being readily understood" that upon the separation of the vehicle chassis and axle the strap will rotate the drum 55 to the le'lt, and consequently the braking mechanism will operate to retard such separation.

Itis necessary to provide means for. taking up slack in the strap which results when the axle is moved towards the chassis. For this purpose 1 provide a helical spring 73, coil-ed around the tubular spacer 59, and having its ends engaged in suitable slots 74 and 7i5 formed in the attaching member 50 and in the brake drum 55 respectively. S ring 7 3' tends to rotate the drum 55 to t e right against the pull of the strap.

A cover plate 76 is mounted outside thebrake drum 55 on the end of the bolt 5l to enclose the strap and other operating mechanisms of the present shock absorber, there being provided in one side of said cover a suitable opening 77 for the end of the strap leading to the axle. In addition, a second plate 78 is secured to the rear face of boss lugs'62, which, with plate 76, completely encloses the braking mechanism. i

I have illustrated in Figs. 6 and 7 an iniproved link mechanism for use in connecting arm 20 of the form of my shock absorber shown in Figs. 1 and 2 to an axle.' This link has been designed to do away with the use of pivotal bearings and studs as used in the present types of connecting links, therefore eliminating much of the wear and rattle which develops in the use of shock absorbers. The outer end of arm 20 is formedwith a flange 80, to which is attached, by means of a bolt 81, a comparatively short piece of flexible material 82, such as ordinary heavy belting. Also attached at its upper end to material S2 is a pressed metal link member 83. which is U-shaped in configuration and has its side -ace of the brake drum and the outer adj acent surface of the brake shoe pi-votal bearing. As has been previously described, as vthe drum is moved to the left (of the drawings), the brake shoe, on account of its frictional engagement therewith, will be moved -to wedge between these two convergent surfaces, which effects a braking action on the rotary movement of the drum.

.Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctl claim as my invention l. lhs combination of a fixed element, a rotatable element disposed about said first element, pivotally mounted segmental friction shoe members ad-apted to move eccentricallyof said rotatable element, the pivotal points of each such shoes being located at the forward ends thereof, and meansI for keeping said shoe pressed outwardly into engagement with said rotatable element.

2. The'eombination of'a fixed element, a rotatable-element concentric withand disposed about said lixed element, segmental friction' shoe members pivotally mounted between said elements, the pivotal points of each such shoes being removed from the axis of said rotatable element, and means for keeping said shoes ressed outwardly into engagement with sai rotatable element.

3. The combination of a supporting element adapted for attachment to a vehicle frame, a rotatable element mounted concentrically of said irstv element, radial projections on said first element, segmental friction shoe members having their forward ends pivotally mounted in said projections, the outer periphery of said shoes being concentric with and lying contiguous to the inner periphery of said rotatable element, and means for keeping the free ends of said shoes pressed outwardly.

4. The combination of a supporting element adapted for attachment to a vehicle frame, a rotatable element mounted concentrically ot said first element, radial projections on said first element, segmental friction shoe members having their forward ends pivtally mounted in said projections, the outer periphery of said shoes being concentric with and lying contiguous to the inner periphery of said rotatable element, and means for connecting said rotatable element with the vehicle axle.

5. The combination of a supporting element adapted for attachment to a vehicle frame, a rotatable element mounted concentrically of said first element, radial projections on said first element, segmental friction shoe members having, their forward ends pivotally mounted in said projections, the outer periphery of said shoes being concentric with and lying contiguous to the inner periphery of said rotatable element, and means for connectinfr said rotatable element with the vehicle axlae, said friction shoes being adapted to move outwardly about their pivots during therotation ot' said rotatable element in one direction and retard such rotary movement.

6. The combination of a fixed supporting element, a. plurality of brake shoes pivotally mounted on said element, a brake drum mounted concentrically of said element and having its outer periphery encircling said brake shoes, the outer surfaces of said shoes being eccentric to their pivotal pointsand concentric with said drum, and means for keeping the free ends of said shoes pressed loutwardly into engagementwith the drum.

' 7. The combination of a rotatable brake drum, and a pivotally mounted brake shoe cooperating with the inner periphery of said drum, the pivotal point ot said shoe being spaced between the axis and the periphery of said drum, and the outer periphery of said shoe being concentric with the inner periphery of said drum.

8. The combination of a rotatable brake drum, a brake shoe pivotally mounted at one end within said drum, the external surface of said shoe being concentric with the inner periphery of said drum, and the pivotal pointof the shoe being eccentric to such external surface, and means for keeping the free end of saidshoe pressed outwardly into engagement with said drum.

9. In a shock absorberof the character described, the combination of a hub member adapted to be attached to a vehicle chassis, a brake drum rotatably mounted about said member, means for connecting said drum to the vehicle axle whereby the drum is oscillated as the frame is moved toward and away from said axle,`and a plurality of segmental brake shoes pivotally carried by said hub member and engaging the inner periphery of said drum to retard the rotary movementthereof in one direction.

10. In a. shock absorber ofthe character described, the combination oi a hub 'member adapted to be attached to a vehicle chassis, a brake drum rotatably mounted about said member, means for connecting said drum to the vehicle axle whereby the drum is oscillated as the frame is moved toward and a way from said axle, a plurality of brake shoes pivotally mounted at one end on said hub lli member, theI outer surface of said shoes being formed eccentric to said pivotal points and concentric with the inner periphery of said drum, and a layer of friction-material on said outer surface of said shoes.

1l. In a shock absorber of the character described, the combination of a hub member adapted to be attached to a vehicle chassis, a bralre drum rotatably mounted `about said member, means for connecting said drum to the vehicle axle whereby the drum is oscillated as the frame is moved toward and away from said axle, a plurality of brake shoes pivotally mounted at one end on said hub member, the outer surface of said shoes being formed eccentric-to said pivotal points and concentric with the inner periphery of said drum, friction material on the outer surface o'f said shoes, and means for keeping the free ends of the shoes pressed outwardly.

12. In a shock absorber of the character described, the combination of a supporting hub member, spaced radially projecting lugs provided on said hub member, a plurality of segmental brake shoes pivotally mounted at one end in said lugs, a brake drum surround. ing the outer en d of said hub and saidshoes, friction elements carried on the outer sur faces of said shoes, the configuration of said outer surfaces being concentric with the inner periphery of said drum but eccentric to the pivotal points of the shoes, and means for keeping the free ends of said shoes pressed outwardly.

13. In a shock absorber of the character described, the combination of a rotatable brake drum, a plurality of equidistantly spaced brake shoes carried interiorly of said drum, each said shoes being provided with a boss at one end, a central non-rotatable hub member having radial lugs extendin adjacent said bosses, pins passing throug each set of said lugs and bosses for pivotally mounting said shoes, and means interposed between said hub member and said shoes for keeping their outer free ends pressed toward said drum.

14. The combination of a supporting element adapted for attachment to a vehicle frame, movable -friction elements 'carried thereby, a rotatable element. supported by said friction elements, and means connecting said rotatable element to the vehicle axle whereby said rotatable'element'A is oscillated as the axle moves toward and away from the frame.

15. The combination of a supporting element adapted for attachment to a vehicle frame, movable friction elements carried thereby, a rotatable element supported by said friction elements, means connecting saidv rotatable element tothe vehicle axle whereby said rotatable elementiisoscillated astheaxle moves toward and away from the frame, and means lfor engaging said friction elements with said rotatable element to retard the rotation thereof in one direction. A

.16. The combination of a supporting element adapted for attachment to a vehicle, friction elements pivotally mounted on said supporting element, said pivotal points being eccentric to the axis of said supporting element, a rotatable element supported by said friction element, and means for oscillatingl -ment,ithe pivotal pointv thereof being eccentric to the axis of the rotatable element, said shoe having its outer surface-concentric with said element and havingvits ends terminating substantially diametrically of said element, and a layer of friction material mounted on each said ends between the shoe and the rotatable element.

19. The combination of a supporting element adapted for attachment to a vehicle, a rotatable element mounted concentrically of said first element, a brake shoe pivotally mounted between said elements and engaging the inner surface of said rotatable element,

said shoe being adapted to wedge against the rotatable element during movement thereof in one direction, and means acting to press said shoe into 'frictional engagement with said rotatable element to retard the movement thereof in the o posite direction.

20. The com inati'on of a rotatable brake drum, a brake shoe pivotally mounted at one end within said drum, the external surface of said shoe being 4concentric with the inner periphery of said drum and the pivotal point of said shoe being eccentric to said external surface whereb movement in one direction will cause said s oe to wedge between the eccentric surfaces of said pivotal point and said brake drum. Y

21. The combination of a rotatable brake drum, a brake shoe pivotally mounted at one end within said drum, the external surface of said shoebeing concentric with the inner periphery of said drum and the pivotal point of sald shoe being eccentric to said external surface whereby movement in one direction 'will cause said shoe to wedge between the eccentric surfaces of said ivotal point and said brake drum and whereb direction will instantly release the wedge act-ion of said shoe.

22. The combination of a rotatable brake y movement in the opposite drum, a brake shoe pivotally mounted at one end within said drum, the external surface of said shoe being concentric withl the inner periphery o f said drum and the pivotal point of sai/d shoe being eccentric to saidY external surface whereby movement in one direction will cause said shoe to wedge between the eccentric surfaces of said pivotal point and said brake drum and means for keeping the free end of said shoe frictionally engaged with said drum to retard the movement thereof -in the oppositedirection.

23. The combinationl of a rotatable brake drum, a brake shoe pivotally mounted at one end within said drum, the external surface of said shoe being concent-ric with the inner periphery of-said drum and the pivotal point of said shoe being eccentric to said external iurface whereby movement in one direction will cause said shoe to wedge between the eccentric surfaces of said pivotalpoint and said brake drum and means for keeping the free end of said shoe frictionally engaged with said drum to retard the movement thereof in the opposite direction, said ,m'eans being adapted to exert a lesser braking action than that caused by said wedging action. 24. The combination of a rotatable brake drum, a brake shoe pivotally mounted at one end within said drum, the external surface of said shoe being concentric with the inner periphe of said drum and the pivotal point of said s oe being eccentric to said external surface whereby movement in one direction will cause said shoe to wedge between the eccentric surfaces of said pivotal point and said brake drum and pressure means for keeping the free end of said shoe frictionally engaged with said drum to retard the movement thereof in the opposite direction and means for varying the pressure of said' pressure means.

25.' The combination of a fixed hub member, "a rotatable brake drum, a brake shoe ivotally mounted between said hub and rake drum, the axes-of said drum and shoe `pivot being eccentric, a spring acting to keep said shoe pressed towards said drum and means for varying the pressure of said spring.

26. yThe. combination of a fixed hub member, a rotatable brake drum, a brake shoe plvotally mounted between said hub and rake drum, the axes of said drum and shoe pivot being eccentric, a spring in between said shoe and hub adapted to v .p said shoe in engagement with sald drum and adga ement wit justable means for varying the pressure of .i

said ring.

27.3ll'he combination of a fixed hub member, arotatable brake drum, a brake shoe ivotallymounted between said hub and brake drum, the axes of said drum and shoe pivot being eccentric, a spring inter sed between said shoe and hub ada ted to eep said shoe in engagement with said drum, adjustable means for varying the pressure of said spring and means for locking said adjusting means in adjusted position.

28. The combination of a ber, a rotatable brake drum, a brake shoe pivotally mounted between said hub and brake drum, the axes of said drum and shoe pivot being eccentric a spring interposed between said shoe and hub adapted to keep said shoe in engagement with said drum, adjustable means for varying the pressure of said spring and means accessible externally of said drum for locking said adjusting means in adjusted position. 4

29. The combination of a fixed hub member, va rotatable brak drum, a brake shoe lpivotally mounted be Ween said hub and rake drum, the axes of `said drum and shoe pivot being eccentric, means inter sed between said shoe and hub adapted to eep said shoe in Aengagement with said drum, and means adjusta le externall of said drum for varying the pressure of sai first means.

30. The combination of a fixed hub member, a rotatable brake drum, a plurality of brake shoes pivotally mounted between said hub and said brake drum, the axes of said drum and shoe pivots being eccentric, springs inte between each 'of said shoes and said ub adapted to keep the former in enthe drum, and a single adjustab e means for varying the pressure of each of said sprin 31. The combination of a fixed hub member a rotatable brake drum, a plurality 'of brake shoes pivotally mounted between said hub and sai brake drum,v the axes of said drum and shoe pivots being eccentric, springs inter sed between each of said shoes and said ub adapted to keep the former in engagement with the drum, a single adjustab e means for varying the ressure of each of said springs, and adjustab e means extending exteriorl of the drum and having means for lockin t e same in adjusted position.

Signed y me this 21 day of May, 1924.

COURTNEY N. MITCHELL.

fixed hub mem- 

